/*******************************************************************************

 * Copyright (c) 2002 - 2005 QNX Software Systems and others.

 * All rights reserved. This program and the accompanying materials

 * are made available under the terms of the Eclipse Public License v1.0

 * which accompanies this distribution, and is available at

 * http://www.eclipse.org/legal/epl-v10.html

 *

 * Contributors:

 *     QNX Software Systems - initial API and implementation

 *******************************************************************************/

#include "exec0.h"

#include <unistd.h>

#include <stdlib.h>

#include <stdio.h>

#include <errno.h>

#include <string.h>

#include <libgen.h>

#include <stdlib.h>

/* from pfind.c */

extern char *pfind(const char *name);

pid_t

exec0(const char *path, char *const argv[], char *const envp[],

      const char *dirpath, int channels[3])

{

	int pipe0[2], pipe1[2], pipe2[2];

	pid_t childpid;

	char *full_path;

	/*

	 * We use pfind() to check that the program exists and is an executable.

	 * If not pass the error up.  Also execve() wants a full path.

	 */ 

	full_path = pfind(path);

	if (full_path == NULL) {

		fprintf(stderr, "Unable to find full path for \"%s\"\n", (path) ? path : "");

		return -1;

	}

	/*

	 *  Make sure we can create our pipes before forking.

	 */ 

	if (channels != NULL) {

		if (pipe(pipe0) < 0 || pipe(pipe1) < 0 || pipe(pipe2) < 0) {

			fprintf(stderr, "%s(%d): returning due to error.\n",

				__FUNCTION__, __LINE__);

			free(full_path);

			return -1;

		}

	}

	childpid = fork();

	if (childpid < 0) {

		fprintf(stderr, "%s(%d): returning due to error: %s\n",

			__FUNCTION__, __LINE__, strerror(errno));

		free(full_path);

		return -1;

	} else if (childpid == 0) { /* child */

		char *ptr;

		chdir(dirpath);

		if (channels != NULL) {

			/* Close the write end of pipe0 */

			if (close(pipe0[1]) == -1)

				perror("close(pipe0[1])");

			/* Close the read end of pipe1 */

			if (close(pipe1[0]) == -1)

				perror("close(pipe1[0])");

			/* Close the read end of pipe2 */

			if (close(pipe2[0]) == -1)

				perror("close(pipe2[0]))");

			/* redirections */

			dup2(pipe0[0], STDIN_FILENO);   /* dup stdin */

			dup2(pipe1[1], STDOUT_FILENO);  /* dup stdout */

			dup2(pipe2[1], STDERR_FILENO);  /* dup stderr */

		}

		/* Close all the fd's in the child */

		{

			int fdlimit = sysconf(_SC_OPEN_MAX);

			int fd = 3;

			while (fd < fdlimit)

				close(fd++);

		}

		if (envp[0] == NULL) {

			execv(full_path, argv);

		} else {

			execve(full_path, argv, envp);

		}

		_exit(127);

	} else if (childpid != 0) { /* parent */

		char b;

		if (channels != NULL) {

			/* close the read end of pipe1 */

			if (close(pipe0[0]) == -1)

				perror("close(pipe0[0])");

			/* close the write end of pipe2 */

			if (close(pipe1[1]) == -1) 

				perror("close(pipe1[1])");

			/* close the write end of pipe2 */

			if (close(pipe2[1]) == -1) 

				perror("close(pipe2[1])");

			channels[0] = pipe0[1]; /* Output Stream. */

			channels[1] = pipe1[0]; /* Input Stream.  */

			channels[2] = pipe2[0]; /* Input Stream.  */

		}

		free(full_path);

		return childpid;

	}

	free(full_path);

	return -1;                  /*NOT REACHED */

}

int wait0(pid_t pid)

{

	int status;

	int val = -1;

	if (pid < 0 || waitpid(pid, &status, 0) < 0)

		return -1;

	if (WIFEXITED(status)) {

		val = WEXITSTATUS(status);

	}

	return val;

}